The invention discloses a pedestrian flow counting method and a pedestrian flow counting device based on an infrared temperature measurement sensor. According to the pedestrian flow counting method, 6 paths of temperature data on a same vertical line are acquired through an infrared temperature measurement sensing part which is placed on the side of an access, whether a person passes by is judged through analyzing the temperature data, whether the incoming and outgoing of the person end is judged by detecting a time interval when nobody passes, thus the incoming and outgoing information can be judged, control and measurement units transmit the incoming and outgoing information of people to an upper machine in real time, and the upper machine can record the current time, count number of people passing by an entrance and number of people passing by an exit within a time period and obtain the number of people in a place through difference between the two numbers, thereby achieving the automatic, accurate and reliable detection of number of the incoming and outgoing people. The pedestrian flow counting device comprises the infrared temperature measurement sensing part, a temperature acquisition/analysis part, a network device and a computer or an embedded processing device serving as the upper machine. The pedestrian flow counting improves the pedestrian flow counting stabilizability, precision and speed, and can be widely applied to entrances or public places.